Quantum radar is a theoretical remote-sensing method based on quantum entanglement. The most convincing model has been proposed by an international team of researchers. This team designed a model of quantum radar for remote sensing of a low-reflectivity target that is embedded within a bright microwave background, with detection performance well beyond the capability of a classical microwave radar. By using a suitable wavelength converter, this scheme generates excellent quantum correlations (quantum entanglement) between a microwave signal beam, sent to probe the target region, and an optical idler beam, retained for detection. The microwave return collected from the target region is subsequently converted into an optical beam and then measured jointly with the idler beam. Such a technique extends the powerful protocol of quantum illumination to its more natural spectral domain, namely microwave wavelengths.
A prototype quantum radar could be realized with current technology, and is suited to various potential applications, from standoff sensing of stealth objects to environmental scanning of electrical circuits. Thanks to its quantum-enhanced sensitivity, this device could also lead to low-flux non-invasive techniques for protein spectroscopy and biomedical imaging.
Alternative methods were also considered by defense contractor Lockheed Martin whose aim was to create a radar system providing a better resolution and higher detail than classical radar could provide.
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